ATL: Ex Tropical Storm EARL - Discussion

[KWT]

I would agree NCweatherwizard the media is just waiting to pounce on this already.The models are in good agreement to keep it for the most part offshore.

Then again on the other hand they were in good agreement in keeping this one east of 65W at one point as well...
Its too close to call, really would not take much of a west shift for this one to come close enough to spread hurricane winds into the Outer Banks.

For sure though the media will have a field day if the NHC track even nudges a little closer then it is.

[eastcoastFL]

how about se new england?

[wxman57]

That's definitely not the case. Cone size and watch areas bear no relation. A hurricane's impact can extend far outside the cone, and the tropical storm conditions often do extend well outside the cone.

Thanks for correcting me Wxman. What you wrote occurred to me a few minutes after I posted, as, just looking at the current tracking map, there are warnings up for some of the Islands (Turks/Caicos and parts of the Bahamas??) even though they're NOT in the cone. My comment was definitely stupid as anyone could see!!!

No, it wasn't a stupid comment. A lot of people associate the cone with the effects of a hurricane. But the cone only represents 66.7% 5-year track error. A hurricane's wind field often extends well outside the cone, particularly the cone out to 2-3 days.

[hurricaneCW]

I think the tracks are pretty much dead on right now, maybe only very slight shifts. Although even a 25-50 mile shift west could place the western core on land.

[SunnyThoughts]

[hohnywx]

According to the 11:00 advisory NHC says a hurricane watch may be posted for portions of the Mid-Atlantic later today. Any ideas where and when? I'm in Va Beach.

I'm not a professional, but my understanding is that watches would be issued for areas in the 3-day NHC cone. You can find that here:

http://www.nhc.noaa.gov/refresh/graphic ... e#contents

That's definitely not the case. Cone size and watch areas bear no relation. A hurricane's impact can extend far outside the cone, and the tropical storm conditions often do extend well outside the cone. And that's even if the center of the hurricane follows the exact forecast path down the middle of the error cone. With Ike, hurricane force winds extended outside the cone from a couple of days before landfall.

Watches are now issued when the impact of tropical storm force winds is expected within 48 hours. Since that won't occur until Thursday night or early Friday morning, the watches will be issued tomorrow, probably in the morning.

I guess you disagree with the NHC then:

GIVEN THE TRACK AND THE LARGE AREA OF TROPICAL STORM FORCE WINDS...A
HURRICANE WATCH WILL LIKELY BE REQUIRED FOR A PORTION OF THE
MID-ATLANTIC COAST LATER TODAY. INTERESTS FROM THE CAROLINAS
NORTHWARD TO NEW ENGLAND SHOULD MONITOR THE PROGRESS OF EARL.
THERE IS STILL CONSIDERABLE UNCERTAINTY AS TO HOW CLOSE THE
HURRICANE WILL COME TO THE U.S. EAST COAST.

[KBBOCA]

I found this discussion from Dr. Jeff Masters blog at Weather Underground to be very helpful in understanding the potential risk to the East Coast. He discusses the models and steering factors in clear layman's terms, and also gives a pretty clear idea of what potential "impact" might be for some of the areas in the 5-day cone:

Jeff Masters writes:

The latest set of computer models runs from 2am EDT (6Z) this morning push Earl's projected track a little closer to the U.S. East Coast, and we now have two of our six reliable models predicting a U.S. landfall. The latest NOGAPS run shows Earl hitting the Outer Banks of North Carolina late Thursday night, then striking Southeast Massachusetts late Friday night, and Eastern Maine on Saturday morning. The HWRF model predicts a strike on Eastern Maine Saturday morning, but keeps Earl offshore from North Carolina and Massachusetts. None of the other computer models show Earl hitting the U.S., but several models bring Earl within 100 - 200 miles of North Carolina's Outer Banks and Southeast Massachusetts. It is likely that Earl will being a 12-hour period of heavy rain and tropical storm force winds of 39+ mph to North Carolina's Outer Banks, beginning on Thursday evening. NHC is giving Cape Hatteras a 12% chance of receiving hurricane force winds. By Friday evening, western Long Island, Rhode Island, and Southeast Massachusetts can expect a 6 - 8 hour period of heavy rain and tropical storm force winds of 39+ mph. NHC is giving Nantucket a 11% chance of receiving hurricane force winds. These odds are 4% for Boston, 6% for Providence, 5% for Eastport, Maine, and 11% for Yarmouth, Nova Scotia. The main determinant of whether Earl hits the U.S. or not is a strong trough of low pressure predicted to move off the U.S. East Coast Friday. This trough, if it develops as predicted, should be strong enough to recurve Earl out to sea. Keep in mind that the average error in position for a 3-day NHC forecast is 185 miles, which is about how far offshore Earl is predicted to be from Cape Hatteras three days from now. The average error in a 4-day forecast is 255 miles, which is about the distance Earl is expected to be from the coast of New England four days from now.

Regardless of Earl's exact track, the U.S. East Coast can expect a long period of high waves beginning on Thursday. Significant beach erosion and dangerous rip currents will be the rule, due to waves that will reach 10 - 15 feet in offshore waters. Waves from Hurricane Danielle killed two swimmers in the U.S. over the weekend and forced hundreds of water rescues along the U.S. East Coast. Earl's waves will be worse, and will likely cause millions of dollars in beach erosion damage.

from here:
http://www.wunderground.com/blog/JeffMa ... rynum=1595

[vbhoutex]

That's definitely not the case. Cone size and watch areas bear no relation. A hurricane's impact can extend far outside the cone, and the tropical storm conditions often do extend well outside the cone.

Thanks for correcting me Wxman. What you wrote occurred to me a few minutes after I posted, as, just looking at the current tracking map, there are warnings up for some of the Islands (Turks/Caicos and parts of the Bahamas??) even though they're NOT in the cone. My comment was definitely stupid as anyone could see!!!

No, it wasn't a stupid comment. A lot of people associate the cone with the effects of a hurricane. But the cone only represents 66.7% 5-year track error. A hurricane's wind field often extends well outside the cone, particularly the cone out to 2-3 days.

Even though I knew that the cone was about % etc. as opposed to effects I think a lot of people get the impression that it is indeed the area where effects of a TC might be felt. IMO, the NHC needs to do some more public education along those lines. Hopefully a lot of people will read it here also and pass along that knowledge. As always thanks for your contributions here Wxman57!!

[sandyb]

Hoping for the best for the East Coast and Nova Scotia. Unless the track shifts significantly west, with the core just offshore, the Outer Banks will have the strongest winds from the N and West, and that could mean significant flooding on the sounds sides of islands. Of course ocean swells can be devastating to oceanfront homes and businesses, but don't let your guard down if you are on the sound side or near rivers and creeks that can rise significantly.

Be sure to use forecasts from local NWS offices for local effects, marine warnings, flood advisories, evacuation information. People inland on the mainland should be safer from storm surge effects but rain could produce significant flooding in low-lying areas. Be prepared for losing power and make sure you know right now if you are in an evacuation zone.

NWS Moorehead discussion snip:

.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 230 PM MON...THE LAST HALF OF THE WEEK WILL CONTINUE TO BE
DEPENDENT ON THE TRACK OF HURRICANE EARL. OFFICIAL NHC TRACK
CONTINUES TO SHOW EARL MAINTAINING MAJOR HURRICANE STATUS...BUT
REMAINING OFFSHORE OF CAPE HATTERAS THU INTO THU NIGHT. MODELS IN
PRETTY GOOD AGREEMENT OVERALL WITH TRACK OF EARL...THOUGH NAM
CONTINUES TO BE SLIGHTLY SLOWER. BEST CHANCE OF RAINFALL WILL BE
ALONG THE COASTAL AREAS...PRIMARILY THE OUTER BANKS. HURRICANE
EARL IS EXPECTED TO IMPACT COASTAL REGIONS THURSDAY AND THURSDAY
NIGHT WITH STRONGER WINDS...INCREASED RIP CURRENT RISK FOR ALL
BEACHES...INCREASED SURF...AND POTENTIAL FOR COASTAL FLOODING. AT
THIS TIME...THERE IS STILL MUCH UNCERTAINTY IN THE TRACK OF THE
SYSTEM. IT WILL CONTINUED TO BE MONITORED AS THE IMPACTS FROM THE
SYSTEM COULD VARY GREATLY DEPENDING UPON THE TRACK.

HURRICANE EARL SHOULD PULL OUT OF THE AREA FRIDAY MORNING WITH
WESTERLY FLOW DRYING THINGS OUT. A WEAK FRONT WILL DROP THROUGH
THE AREA SATURDAY MORNING BUT WITH LIMITED MOISTURE. HAVE KEPT
SLIGHT CHANCE WITH THE FRONT. HIGH PRESSURE WILL BUILD IN TO THE
NORTH OF THE AREA SUN-MON.

Moorehead forecast office Home:
http://www.erh.noaa.gov/er/mhx/

Great info, even though you mispelled Morehead!

Stay east, Earl, stay east!

yea its Morehead but if you don't live you you dont know

[Javlin]

I would agree NCweatherwizard the media is just waiting to pounce on this already.The models are in good agreement to keep it for the most part offshore.

Then again on the other hand they were in good agreement in keeping this one east of 65W at one point as well...
Its too close to call, really would not take much of a west shift for this one to come close enough to spread hurricane winds into the Outer Banks.

For sure though the media will have a field day if the NHC track even nudges a little closer then it is.

That's true KWT but no need in crossing that bridge till one has to let's see what Earl does today looks to be gaining alittle more latitude and slowing down.A turn can happen much moreso in this enviroment than what was 24-36hrs ago with the other steering currents.

[hurricaneCW]

Earl is spitting out a huge outflow boundary right now. This is certainly indicative of a weakening system. I also see a lot of dry trying to tear down the western half of the system. An EWRC could overall help the system ramp up because I expect it to weaken to a Cat 2 later today.

[wxman57]

I guess you disagree with the NHC then:

GIVEN THE TRACK AND THE LARGE AREA OF TROPICAL STORM FORCE WINDS...A
HURRICANE WATCH WILL LIKELY BE REQUIRED FOR A PORTION OF THE
MID-ATLANTIC COAST LATER TODAY. INTERESTS FROM THE CAROLINAS
NORTHWARD TO NEW ENGLAND SHOULD MONITOR THE PROGRESS OF EARL.
THERE IS STILL CONSIDERABLE UNCERTAINTY AS TO HOW CLOSE THE
HURRICANE WILL COME TO THE U.S. EAST COAST.

Nothing in that statement above that I'd disagree with as far as the extent of the watch. The 48-hr time period before impact does occur late tonight. Often, the NHC will issue watches 60 hours in advance of potential impact, particularly when the 48hr point occurs before sunrise. And a big, powerful hurricane might warrant warnings being put out a bit before the 48hr point.

[lovestorms84]

http://www.wunderground.com/tropical/tr ... ml#a_topad

Great tracking site

[Extremeweatherguy]

Earl is spitting out a huge outflow boundary right now. This is certainly indicative of a weakening system. I also see a lot of dry trying to tear down the western half of the system. An EWRC could overall help the system ramp up because I expect it to weaken to a Cat 2 later today.

That outflow boundary is coming from a far outer band of Earl, not the inner core, and thus I doubt it will lead to any weakening of the system. In fact, I think it is very possible that Earl could actually strengthen slightly later today as it completes the EWRC it is currently undergoing.

[kevin]

Is there any possibility the trough that will push this off to sea might not materialize?

[tailgater]

CourierPR In the interest of accuracy, I don't think there is a ULL to Earl's NW. An advancing front is what is supposed to cause the turn

I should have said (ULL)is NNW, but it is diving SSW rather quickly. That's just the way it looks to me. I know the trough is supposed to turn it later in the week but this may help steer it farther off the coast.
http://mkwc.ifa.hawaii.edu/satellite/sa ... verlay=off

Notice the circulation is clockwise, which if I'm not mistaken, is high pressure.

Not sure if that was sarcasm or not but the feature I'm talking about is at 68w 36N and is rotating CCW and as I said before it's weak and may not have any influence at all on Earl.

[ncweatherwizard]

Earl is spitting out a huge outflow boundary right now. This is certainly indicative of a weakening system. I also see a lot of dry trying to tear down the western half of the system. An EWRC could overall help the system ramp up because I expect it to weaken to a Cat 2 later today.

The dry air won't help, but unless shear degrades the inner core (quite possible in a day or two), it won't really hurt. The western half of the hurricane is exposed to some westerly flow aloft, and you're seeing its effects on the cirrus outflow. So you might see some subsidence well away from the inner core as dry air fills in.

[Javlin]

Is there any possibility the trough that will push this off to sea might not materialize?

Oh it's coming looks to be in Oregon if I am reading this right and what a high in front of Earl

http://mapcenter.hamweather.com/satelli ... ?s=800x600

[sandyb]

I would agree NCweatherwizard the media is just waiting to pounce on this already.The models are in good agreement to keep it for the most part offshore.

Talking to folks in the Hampton Roads region, it seems like the local news media hasn't yet gone crazy. So kudos to them there. I just don't want them to have an excuse to overexpose the threat until necessary because people do get tired of hearing it and some will grow complacent if they perceive a false alarm.

i think they are keeping it low key due to the last big holiday weekend of the summer...we have hotels here complaining that they are empy this weekend

[ncweatherwizard]

CourierPR In the interest of accuracy, I don't think there is a ULL to Earl's NW. An advancing front is what is supposed to cause the turn

I should have said (ULL)is NNW, but it is diving SSW rather quickly. That's just the way it looks to me. I know the trough is supposed to turn it later in the week but this may help steer it farther off the coast.
http://mkwc.ifa.hawaii.edu/satellite/sa ... verlay=off

Notice the circulation is clockwise, which if I'm not mistaken, is high pressure.

Not sure if that was sarcasm or not but the feature I'm talking about is at 68w 36N and is rotating CCW and as I said before it's weak and may not have any influence at all on Earl.

That's NNE (of the future track)

GFS brings this ULL southwestward then lifts and dissipates it--all within two days. Might provide some shear to keep Earl from strengthening.